diff --git a/tests/scripts/generate_bignum_tests.py b/tests/scripts/generate_bignum_tests.py
index 89d0ac2..c3058e9 100755
--- a/tests/scripts/generate_bignum_tests.py
+++ b/tests/scripts/generate_bignum_tests.py
@@ -78,6 +78,7 @@
                       metaclass=ABCMeta):
     #pylint: disable=abstract-method
     """Common features for bignum operations in legacy tests."""
+    unique_combinations_only = True
     input_values = [
         "", "0", "-", "-0",
         "7b", "-7b",